Tropical Depression KROVANH (22W) Tracker

WTPN31 PGTW 061500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL DEPRESSION 22W (KROVANH) WARNING NR 022//
RMKS/
1. TROPICAL DEPRESSION 22W (KROVANH) WARNING NR 022    
   01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   061200Z --- NEAR 25.7N 131.0E
     MOVEMENT PAST SIX HOURS - 075 DEGREES AT 07 KTS
     POSITION ACCURATE TO WITHIN 030 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   REPEAT POSIT: 25.7N 131.0E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   070000Z --- 26.6N 132.1E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 24 HR POSIT: 020 DEG/ 06 KTS
    ---
   24 HRS, VALID AT:
   071200Z --- 27.8N 132.6E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 36 HR POSIT: 005 DEG/ 08 KTS
    ---
   36 HRS, VALID AT:
   080000Z --- 29.3N 132.8E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 48 HR POSIT: 005 DEG/ 09 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   081200Z --- 31.0N 133.0E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 60 HR POSIT: 030 DEG/ 10 KTS
    ---
   60 HRS, VALID AT:
   090000Z --- 32.7N 134.1E
   MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   VECTOR TO 72 HR POSIT: 050 DEG/ 13 KTS
    ---
   72 HRS, VALID AT:
   091200Z --- 34.3N 136.5E
   MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
    ---
REMARKS:
061500Z POSITION NEAR 25.9N 131.3E. 06SEP26. TROPICAL DEPRESSION 22W 
(KROVANH), LOCATED APPROXIMATELY 179 NM EAST-SOUTHEAST OF KADENA AB, 
HAS TRACKED EAST-NORTHEASTWARD AT 07 KNOTS OVER THE PAST SIX HOURS.
MINIMUM CENTRAL PRESSURE AT 061200Z IS 989 MB. MAXIMUM SIGNIFICANT 
WAVE HEIGHT AT 061200Z IS 14 FEET. NEXT WARNINGS AT 062100Z, 070300Z, 
070900Z AND 071500Z.//
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WDPN31 PGTW 061500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 22W (KROVANH) 
WARNING NR 022//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.7N 131.0E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 179 NM EAST-SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 14 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
DEPRESSION 22W (KROVANH) WITH A FULLY EXPOSED LOW-LEVEL CIRCULATION
CENTER (LLCC) AND FLARING CONVECTION CONFINED TO THE SOUTHWESTERN
QUADRANT. 22W HAS STALLED IN PLACE SINCE 061000Z, JUST SOUTHWEST OF
MINAMI DAITO JIMA. PRESSURE READINGS FROM SURFACE OBSERVATIONS ON
THE ISLAND HAVE DROPPED TO 990 MB AS THE CIRCULATION INCHES CLOSER.
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE
EXPOSED LLCC IN ANIMATED EIR IMAGERY. THE INITIAL INTENSITY OF 30
KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK
FIXES AND CIMSS INTENSITY ESTIMATES LISTED BELOW. ENVIRONMENTAL
ANALYSIS INDICATES THAT 22W REMAINS IN A MARGINAL ENVIRONMENT
CHARACTERIZED BY MODERATE POLEWARD OUTFLOW ALOFT, 15-20 KTS
SOUTHEASTERLY VERTICAL WIND SHEAR, DRY AIR ENTRAINMENT, AND WARM
(28-29 C) SEA SURFACE TEMPERATURES.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: THE NORTHERN PERIPHERY OF AN ELONGATED
NEAR EQUATORIAL RIDGE (NER) POSITIONED TO THE SOUTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.0 - 30 KTS
   KNES: T2.0 - 30 KTS
   CIMSS ADT: 34 KTS AT 061140Z
   CIMSS AIDT: 36 KTS AT 061140Z
   CIMSS D-MINT: 28 KTS AT 060824Z
   CIMSS D-PRINT: 28 KTS AT 061140Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT FROM THE WEST


ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TD 22W IS FORECAST TO BEGIN TURNING
NORTHEASTWARD WITHIN THE NEXT 6 HOURS AS THE PRIMARY STEERING
MECHANISM TRANSITIONS TO THE SUBTROPICAL RIDGE CENTERED TO THE
SOUTHEAST OF JAPAN. 22W WILL THEN TRACK GENERALLY NORTHWARD, ALONG
THE WESTERN PERIPHERY OF THE RIDGE THROUGH TAU 48. FOLLOWING TAU
48, THE TRAJECTORY IS EXPECTED TO BECOME MORE NORTHEASTWARD WITH AN
INCREASING SPEED OF ADVANCE AS THE SYSTEM TRACKS ALONG THE
NORTHWESTERN EXTENT OF THE RIDGE. 22W IS FORECAST TO SKIRT 
THE SOUTHERN COAST OF JAPAN AFTER TAU 60 WITH THE REMNANT VORTEX 
PASSING SOUTH OF KYOTO, AROUND TAU 72. IN TERMS OF INTENSITY, 22W
IS FORECAST TO MAINTAIN ITS CURRENT INTENSITY OF 30 KTS THROUGH TAU
48 UNDER THE EFFECTS OF THE MARGINAL ENVIRONMENT. WHILE DRY AIR
ENTRAINMENT IS EXPECTED TO WORSEN, POLEWARD OUTFLOW WILL IMPROVE DUE
TO THE SYSTEM TAPPING INTO A JET STREAK EXTENDING OVER NORTHERN
HONSHU. AFTER TAU 48, SOUTHEASTERLY SHEAR WILL GREATLY INCREASE, 
CAUSING 22W TO WEAKEN AS IT APPROACHES SOUTHERN JAPAN. DISSIPATION IS
FORECAST TO OCCUR AT AROUND TAU 72, AS THE SHALLOW VORTEX ACCELERATES
NORTHEASTWARD AND INTERACTS WITH THE MOUNTAINOUS TERRAIN OF THE
SHIKOKU AND KANSAI REGIONS. 

MODEL DISCUSSION: MODEL TRACK GUIDANCE IS IN MODERATE AGREEMENT
THROUGH TAU 48 WITH A CROSS-TRACK SPREAD OF ABOUT 100 NM. THE ECMWF
AND EC-AIFS MAKE UP THE WESTERNMOST TRACKERS WHILE THE GFS AND GEFS
MEAN MAKE UP THE EASTERNMOST TRACKERS. AFTER TAU 48 THE ALONG-TRACK
SPREAD INCREASES SIGNIFICANTLY DUE TO VARYING TRACK SPEEDS AROUND
THE RIDGE AXIS. THE GFS AND THE EXPERIMENTAL GOOGLE DEEPMIND
ENSEMBLE MEAN ARE QUICKER TO ROUND THE RIDGE WHILE THE JGSM,
NAVGEM, AND ECMWF ARE SLOWER. AT TAU 72 THE ALONG-TRACK SPREAD IS
MEASURED TO BE OVER 350 NM, CAUSING THERE TO BE LESS CONFIDENCE IN
THE FORECAST TRACK PAST THE TAU 48 MARK. THE JTWC TRACK FORECAST IS
SITUATED NEAR THE CONSENSUS THROUGH TAU 48 AND THEN CLOSER TO THE
GOOGLE DEEPMIND THROUGH TAU 72. INTENSITY GUIDANCE CONTINUES TO
HAVE A SLIGHT SPLIT BETWEEN THE MODELS WITH THE PRIMARY OUTLIER
BEING HAFS-A. THE REMAINDER OF GUIDANCE SHOWS A STEADY INTENSITY
THROUGH TAU 48 FOLLOWED BY WEAKENING WHILE HAFS-A SHOWS A BRIEF
PERIOD OF INTENSIFICATION FROM TAU 36 TO TAU 60 WITH A PEAK
INTENSITY OF AROUND 40 KTS. THE JTWC INTENSITY FORECAST REFLECTS
THE SAME PHILOSOPHY AS THE PREVIOUS WARNING, AND IS PLACED WITH
MEDIUM CONFIDENCE.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   INTENSITY 00-72 HR: MEDIUM//
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